Coloborhynchus
Name:
Coloborhynchus
(Maimed beak).
Phonetic: Co-lo-bo-rink-us.
Named By: Richard Owen - 1874.
Synonyms: Amblydectes.
Possibly also
Ptenodactylus, Santanadactylus, Siroccopteryx,
Uktenadactylus.
Classification: Chordata, Reptilia,
Pterosauria, Pterodactyloidea, Ornithocheiridae.
Species: C. clavirostris
(type).
Also C. capito ,C. fluviferox, C. sedgwicki, C.
araripensis, C.
robustus, C. ligabuei, C. piscator.
Diet: Piscivore.
Size: Largest species up to 6 meter wingspan.
Largest skull length up to 75 centimetres long.
Known locations: Brazil - Santana Formation.
England - Cambridge Greensand. USA, Texas.
Time period: Aptian to Albian of the Cretaceous.
Fossil representation: Several specimens, but
usually of fragmentary remains.
The
forward dentition of Coloborhynchus was quite
special with the front
two teeth pointing forwards, and the immediate three pairs of teeth
behind them pointing to the sides. This tooth arrangement would have
made it much easier for Coloborhynchus to catch and
carry fish out of
the water. The remaining teeth behind the front just pointed down.
Coloborhynchus also had a keeled crest on the tip
of its snout which
was widest at its base and grew steadily thinner towards the top.
Many
species have been assigned to Coloborhynchus,
however because the
type specimen was described from only a partial upper jaw, it is
uncertain how valid these species actually are. Usually the only
thing that can be used is the way that the tooth sockets are arranged.
The
genus Coloborhynchus was created when Richard Owen
rejected Harry
Govier Seeley's creation of the Ornithocheirus
genus from the various
unnamed fossils that had been recovered from the Cambridge Greensand.
This name change was actually conceived upon the grounds that Owen
disagreed with the name 'bird hand' being used for a reptile.
Owen also created a second genus called Criorhynchus.
Coloborhynchus
was founded upon the basis that the two front teeth were the defining
trait. However in 1914 Reginald Walter Hooley declared this trait
as actually created by erosion of the fossil and were not
representative of the living creature. Hooley absorbed Coloborhynchus
into Criorhynchus, a decision that would be
accepted for most of the
twentieth century.
In
1992 a pterosaur snout was recovered from the Paw Paw Formation of
Texas, and this would start a shift towards re-evaluating the genus
because when named in 1994 by Yuong-Nam Lee it was given the name
Coloborhynchus wadleighi. This was the first use
of the
Coloborhynchus genus since it was absorbed into Criorhynchus
although
it has proved to be a dubious one. When re-examined in 2008 by
Taissa Rodriguez and Alexander Kellner, the snout was assigned to a
new genus called Uktendactylus, although some
consider this genus to
actually be dubious.
More
material found in the Brazilian Santana Formation was referred to
Coloborhynchus at the start of the twenty-first
century, however the
material seemed to differ slightly from the original specification of
Coloborhynchus by the lack of a snout crest. This
has further
complicated classification with material once associated with other
pterosaurs being assigned to the Coloborhynchus
genus. Furthermore,
some researchers think that many of the South American pterosaurs
cannot be assumed to belong to existing European pterosaurs because of
subtle differences between specimens, as well as the fact that many
specimens are so poorly preserved.
The
history of Coloborhynchus is convoluted to say the
least, and the
future looks like is going to be no clearer unless someone can find an
amazingly well preserved specimen. A former species of Coloborhynchus,
C. Spielbergi, has been moved into the Maaradactylus
genus.
Further reading
- Review of the pterodactyloid pterosaur Colobrohynchus.
- T. Rodrigues
& A. W. A. Kellner - 2008.
- The world's largest toothed pterosaur, NHMUK R481, an incomplete
rostrum of Coloborhynchus capito (Seeley 1870) from
the Cambridge
Greensand of England. - Cretaceous Research. - D. M. Martill &
D. M. Unwin - 2011.
- First occurrence of the pterosaur Coloborhynchus
(Pterosauria,
Ornithocheiridae) from the Wessex Formation (Lower Cretaceous) of the
Isle of Wight, England., 126, 3, Proceedings of the Geologists'
Association, pp. 377–380. - David M. Martill - 2015.
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